Merging upstream version 2.0.3+dfsg (Closes: #923993, #1042533, #1045145).

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 56 insertions, 0 deletions

diff --git a/src/go/pkg/matcher/cache.go b/src/go/pkg/matcher/cache.go
new file mode 100644
index 000000000..4594fa06f
--- /dev/null
+++ b/src/go/pkg/matcher/cache.go
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package matcher
+
+import "sync"
+
+type (
+	cachedMatcher struct {
+		matcher Matcher
+
+		mux   sync.RWMutex
+		cache map[string]bool
+	}
+)
+
+// WithCache adds cache to the matcher.
+func WithCache(m Matcher) Matcher {
+	switch m {
+	case TRUE(), FALSE():
+		return m
+	default:
+		return &cachedMatcher{matcher: m, cache: make(map[string]bool)}
+	}
+}
+
+func (m *cachedMatcher) Match(b []byte) bool {
+	s := string(b)
+	if result, ok := m.fetch(s); ok {
+		return result
+	}
+	result := m.matcher.Match(b)
+	m.put(s, result)
+	return result
+}
+
+func (m *cachedMatcher) MatchString(s string) bool {
+	if result, ok := m.fetch(s); ok {
+		return result
+	}
+	result := m.matcher.MatchString(s)
+	m.put(s, result)
+	return result
+}
+
+func (m *cachedMatcher) fetch(key string) (result bool, ok bool) {
+	m.mux.RLock()
+	result, ok = m.cache[key]
+	m.mux.RUnlock()
+	return
+}
+
+func (m *cachedMatcher) put(key string, result bool) {
+	m.mux.Lock()
+	m.cache[key] = result
+	m.mux.Unlock()
+}